Neural Tuning for Sound Duration: Role of Inhibitory Mechanisms in the Inferior Colliculus

TLDR

Duration is a biologically important feature of sound, and neurons in the bat inferior colliculus are tuned to it, yet the level and neural mechanisms underlying this tuning remain unclear. The study proposes a model to explain how duration tuning arises in the bat inferior colliculus. The model posits that an early, sustained inhibitory input creates a temporal window that allows a later, transient excitatory input to drive firing. Blocking GABA or glycine receptors eliminates duration tuning, and patch‑clamp recordings show that inhibition establishes the temporal frame for excitation.

Abstract

Duration is a biologically important feature of sound. Some neurons in the inferior colliculus of the big brown bat, Eptesicus fuscus , are tuned to sound duration, but it is unclear at what level the tuning originates or what neural mechanisms are responsible for it. The application of antagonists of the inhibitory neurotransmitters γ-aminobutyric acid or glycine to neurons in the inferior colliculus eliminated duration tuning. Whole-cell patch-clamp recordings of synaptic currents suggested that inhibition produces a temporal frame within which excitation can occur. A model is proposed in which duration tuning arises when an early, sustained inhibitory input interacts with a delayed, transient excitatory input.